This invention relates in general to wheelchairs and more particularly to adjustable wheelchairs.
Wheelchairs are adapted to meet size requirements of users, seeking to provide a suitable seat height, frame depth, wheelbase and width. Wheelchair frames are commonly either fabricated to a custom specification or adjusted by using components that can be moved relative to a frame.
Custom fabricated frames, often described as rigid frame wheelchairs, have a limitation of not having any adjustment or a very limited range of adjustment. When user changes occur, the frame may not be adaptable to meet future needs. The advantage of the rigid frame is compact size and reduced weight, but specification has to be very accurate and cost of custom fabrication is higher.
Frames with adjustable components, typically for front and rear wheels, provide an over-sized framework that allows mounting brackets to be moved in both a vertical and horizontal range on the frame, allowing the wheelbase to change in length and the frame to be adjusted in height relative to the wheelbase. The limitation of this approach is that additional frame geometry is required to provide range of adjustment, adding size and weight to the wheelchair.